Numerical Simulation Of Bilateral Synchronous Laser Beam Welding For T-Joint Of Aluminum Alloys

Thin-walled laser welded aluminum alloy structures can decrease weight, reduce cost and increase the loading capability over conventional riveting. However, laser welding parameters, high residual stresses and distortion have restricted the wide application of aluminum alloy T-joint of BSLBW(bilateral synchronous laser beam welding). Research on experimental and finite element numerical simulation of BSLBW was carried out on T-joint composed of aluminum alloy 6156 plate and 6056 flitch. Numerical simulation was conducted for different laser welding parameters.Experimental and finite element numerical simulation was carried out to obtain the influence of laser power and weld velocity on weld configuration. The most optimized welding parameters of BSLBW are obtained on T-joint of aluminum alloy plate.A sequentially coupled thermal-mechanical analysis on basic specimen of one flitch is undertaken to predict the welding temperature field, residual stress and distortion distribution field. A comparison between the experimental and simulation results shows a good agreement. The result indicated that the temperature grades nearby weld pool were much greater. Longitudinal residual stress of T-joint weld is obviously higher than that of the transverse stress, longitudinal compression stress distribution focused on a very small range, and the peak stress reaches 350MPa. Welding distortion of the basic specimen increases with the welding energy increasing.Three-dimensional finite element model of the typical three flitch specimen has been developed to simulate the temperature field, residual stress distribution and distortion. Experimental testing was carried out to measure the distortions of the typical specimens and verify the FE results. The welding of the typical specimen composed of three flitch and base plate in different welding sequences was simulated to find out welding sequence of the smallest distortion. The distortion controlling measure was proposed. Seven flitch specimens in different welding sequences were calculated to identity the welding sequence of the smallest distortion.Research results can guide manufacturing process of airliner fuselage wall plate to improve production efficiency and reduce testing cost. This research enhances the application of high-strength aluminum alloy BSLBW in the astronautic field...